<template>

  <div class="app-container">
    <!--查询表单-->
    <el-form :inline="true" class="demo-form-inline">
      <!--所属分类  一级分类-->
      <el-form-item label="课程类别">
        <el-select
          v-model="searchObj.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged">
          <el-option
            v-for="subject in subjectNestedList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>

        <!--所属分类  二级分类-->
        <el-select
          v-model="searchObj.subjectId"
          placeholder="二级分类">
          <el-option
            v-for="subject in subSubjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>

      <!--标题-->
      <el-form-item>
        <el-input v-model="searchObj.title" placeholder="课程标题"/>
      </el-form-item>

      <!--讲师-->
      <el-form-item>
        <el-select
          v-model="searchObj.teacherId"
          placeholder="请选择讲师">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>

      <el-button type="primary" icon="el-icon-search" @click="fetchData()">查询</el-button>
      <el-button type="default" @click="resetData()">清空</el-button>

      <!--页面数据-->
      <el-table
        v-loading="listLoading"
        :data="list"
        element-loading-text="数据加载中"
        border
        fit
        highlight-current-row
        row-class-name="myClassList">

        <el-table-column
          label="序号"
          width="70"
          align="center">
          <template slot-scope="scope">
            {{ (page - 1) * limit + scope.$index + 1 }}
          </template>
        </el-table-column>

        <el-table-column
          label="课程信息"
          width="470"
          align="center">
          <template slot-scope="scope">
            <div class="info">
              <div class="pic">
                <img :src="scope.row.cover" alt="scope.row.title" width="150px">
              </div>
              <div class="title">
                <a href="">{{ scope.row.title }}</a>
                <p>{{ scope.row.lessonNum }}课时</p>
              </div>
            </div>
          </template>
        </el-table-column>

        <el-table-column
          label="创建时间"
          align="center">
          <template slot-scope="scope">
            {{ scope.row.gmtCreate.substr(0, 10) }}
          </template>
        </el-table-column>

        <el-table-column
          label="发布时间"
          align="center">
          <template slot-scope="scope">
            {{ scope.row.gmtModified.substr(0, 10) }}
          </template>
        </el-table-column>

        <el-table-column
          label="价格"
          width="100"
          align="center">
          <template slot-scope="scope">
            {{ Number(scope.row.price) === 0 ? '免费' : '￥' + scope.row.price.toFixed(2) }}
          </template>
        </el-table-column>

        <el-table-column
          label="付费学员"
          prop="buyCount"
          width="100"
          align="center">
          <template slot-scope="scope">
            {{ scope.row.buyCount }}人
          </template>
        </el-table-column>

        <el-table-column
          label="操作"
          width="150"
          align="center">
          <template slot-scope="scope">
            <router-link :to="'/edu/course/info/' + scope.row.id">
              <el-button size="mini" icon="el-icon-edit">编辑课程信息</el-button>
            </router-link>

            <router-link :to="'/edu/course/chapter/' + scope.row.id">
              <el-button size="mini" icon="el-icon-edit">编辑课程大纲</el-button>
            </router-link>

            <el-button type="danger" size="mini" icon="el-icon-delete" @click="removeDataById(scope.row.id)">删除</el-button>
          </template>
        </el-table-column>
      </el-table>

      <!--分页插件-->
      <el-pagination
        :current-page="page"
        :page-size="limit"
        :total="total"
        style="padding: 30px 0; text-align: center;"
        layout="total, prev, pager, next, jumper"
        @current-change="fetchData"/>
    </el-form>
  </div>
</template>

<script>
import course from '@/api/edu/course'
import teacher from '@/api/edu/teacher'
import subject from '@/api/edu/subject'
export default {

  data() {
    return {
      listLoading: true, // 是否显示loading信息
      list: null, // 数据列表
      total: 0, // 总记录数
      page: 1, // 当前页码
      limit: 10, // 每页记录数
      searchObj: { // 查询条件
        title: '', // 标题
        teacherId: '', // 教师id
        subjectParentId: '', // 一级分类id
        subjectId: '' // 二级分类id
      },
      teacherList: [], // 讲师列表
      subjectNestedList: [], // 一级分类列表
      subSubjectList: [] // 二级分类列表
    }
  },

  created() {
    this.fetchData() // 初始化数据
    this.initSubjectList() // 初始化分类列表
    this.initTeacherList() // 初始化讲师列表
  },

  methods: {
    // 初始化数据
    fetchData(page = 1) {
      this.page = page
      this.listLoading = true
      course.getPageList(this.page, this.limit, this.searchObj).then(result => {
        if (result.success === true) {
          this.list = result.data.rows
          this.total = result.data.total
        }
        this.listLoading = false
      })
    },

    // 初始化讲师列表
    initTeacherList() {
      teacher.getList().then(result => {
        if (result.success === true) {
          this.teacherList = result.data.items
        }
      })
    },

    // 初始化分类列表
    initSubjectList() {
      subject.getNestedTreeList().then(result => {
        if (result.success === true) {
          this.subjectNestedList = result.data.items
        }
      })
    },

    // 改变一级分类后，二级分类跟随改变
    subjectLevelOneChanged(value) {
      for (let i = 0; i < this.subjectNestedList.length; i++) {
        if (this.subjectNestedList[i].id === value) {
          this.subSubjectList = this.subjectNestedList[i].children
          this.searchObj.subjectId = '' // 在每次修改了一级分类后，置空二级分类以供选择
        }
      }
    },

    // 清空
    resetData() {
      this.searchObj = {}
      this.subSubjectList = []
      this.fetchData()
    },

    // 根据id删除课程
    removeDataById(id) {
      this.$confirm('此操作将永久删除课程，以及该课程下的章节和视频，是否继续？', '提示', {
        cancelButtonText: '取消',
        confirmButtonText: '确定',
        type: 'warning'
      }).then(() => {
        return course.removeById(id)
      }).then(() => {
        this.fetchData()
        this.$message({
          type: 'success',
          message: '删除成功'
        })
      }).catch((reason) => {
        if (reason === 'cancel') {
          this.$message({
            type: 'info',
            message: '已取消删除'
          })
        } else {
          this.$message({
            type: 'error',
            message: '删除失败'
          })
        }
      })
    }

  }

}
</script>

<style scoped>
  .myClassList .info {
    width: 450px;
    overflow: hidden;
  }
  .myClassList .info .pic {
    width: 150px;
    height: 90px;
    overflow: hidden;
    float: left;
  }
  .myClassList .info .pic a {
    display: block;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
  }
  .myClassList .info .pic img {
    display: block;
    width: 100%;
  }
  .myClassList td .info .title {
    width: 280px;
    float: right;
    height: 90px;
  }
  .myClassList td .info .title a {
    display: block;
    height: 48px;
    line-height: 24px;
    overflow: hidden;
    color: #00baf2;
    margin-bottom: 12px;
  }
  .myClassList td .info .title p {
    line-height: 20px;
    margin-top: 5px;
    color: #818181;
  }
</style>
